A. Field of the Invention
The present invention relates to a medical treatment apparatus utilizing an ultrasonic wave and used for a treatment for breaking up, e.g., a stone formed in a living body.
B. Description of the Prior Art
Conventional ultrasonic treatment apparatuses are known to break up various stones (e.g., a gallstone formed in a bile duct and ureteral stones formed in a ureter, a renal pelvis, and calyxes) formed in living bodies.
Such a conventional ultrasonic treatment apparatus comprises a vibration generator and an insertion portion with a vibration transmission member. Various stones formed in living bodies are broken up by ultrasonic vibrations transmitted by the vibration transmission member. In particular, in an ultrasonic treatment apparatus having a flexible vibration transmission member, an insertion portion is inserted in an arcuated portion such as a bile duct through a treatment channel of an endoscope.
The vibration transmission member of the above-mentioned ultrasonic treatment apparatus is made of a stainless pipe, a metal wire or the like. The inner wall of the endoscope channel is made of a resin tube such as a GORE-TUBE (GORE-TEX INC.). The vibration transmission member is inserted in a body cavity through the channel of the endoscope. In this case, the edge of the vibration transmission member undesirably damages the inner wall of the channel.
In a conventional ultrasonic treatment apparatus wherein the ultrasonic transmission member of the insertion portion is entirely enclosed with a cover, the inner wall of the channel is not damaged when the transmission member is inserted in the channel of the endoscope. However, when a stone or thrombus is to be eliminated, the efficiency of the vibration transmission from the distal end of the ultrasonic treatment to an object to be broken up is degraded. As a result, the object cannot be satisfactorily broken up.